Correlation between plasma parameters and structure of thin TiO2 films deposited by conventional and pulsed magnetron sputtering methods

The aim of the work was to diagnose plasmas excited by two magnetron sputtering techniques: conventional reactive magnetron sputtering (RMS) and magnetron sputtering realized under gas impulse conditions (GIMS) with use of light emission spectroscopy and Langmuir probing. The plasmas were studied during deposition of TiO2 coatings by magnetron sputtering of Ti target in O2 atmosphere. The obtained deposits were investigated with use of infrared spectroscopy (FTIR) and X-ray diffraction (GIXRD). Two major conclusions were drawn from the investigations. One concerned the mechanism of TiO2 formation during reactive sputtering. An absence of emission lines corresponding to plain Ti atoms proves that their oxidation takes place at the surface of the Ti target without any gas phase reactions. The second conclusion concerned deposition thermodynamics. Although the diagnostics of the GIMS plasma revealed a greater plasma density and electron temperature than in the RMS one, it was the latter technique that produced more high temperature polymorph of TiO2. It appears that the pulse technique offers a way to control thermodynamic conditions of deposition in a broad range up to a conversion to the RMS mode of deposition.